Chip card reading devices are also known in the art as CCAD (chip card acceptor devices). These chip card reading devices can accept either chip cards having a standard thickness or having twice said standard thickness, i.e. double thickness. A chip card reading device adapted to read chip cards of different thicknesses is presently not known.
The receptacle of chip card reading devices for standard thickness cards is too narrow to accept also cards having double thickness. Chip card reading devices for double thickness cards can accept cards having the standard thickness, however, contacting problems arise in this case. If the difference in thickness of the chip cards is to be accommodated by elastic contacting elements of the chip card reading device, due to the larger amount of bending of the contacting elements and the larger required displacement thereof, it is not possible to keep the contacting force of the contacting elements on the corresponding contact pads of the chip card within the allowable range of 0.3 to 0.5N.
U.S. Pat. No. 5,012,078 discloses an IC card reader which comprises a rocking lever including a central pivot, an actuating cam on one side of the pivot and against which a card being inserted comes to bear at the end of its insertion stroke, thereby pivoting the lever from a rest position to a pressure-applying position, a pressure cam on the other side of the pivot for bearing against the card when the rocking lever is in its pressure-applying position, thereby bending the card towards the contact elements, and resilient return means returning the rocking lever to its rest position when it is not engaged by a card inserted in the reader. This reference does not consider cards having different thicknesses. Further, the stresses and strains imposed on the card when bent by said cam in the reading position will lead to premature failure of the contact pads and/or the circuit comprised on the card.
German Patent Application DE 43 36 192 shows a chip card reading device in which a rocking lever similar to the one disclosed in the above U.S. patent is actuated by a card being inserted into the chip card reader. An actuating cam of the rocking lever acts on the contacting elements of the reader to press them against the the card. This reference does not consider cards having different thicknesses either. If cards of different thicknesses were used with this card reader, it would not be possible to keep the contacting force of the contacting elements on the corresponding contact patches of the chip card within the allowable range of 0.3 to 0.5N.
Finally, German Utility Model No. G 94 00 348 discloses a chip card reader which comprises a frame, a movable carrier within said frame for receiving the chip card, a lever pivotably mounted on said frame and comprising a pressure plate at one end thereof and a cam track, and a stationary roller cam rotatably mounted on said frame. Upon insertion of a chip card into said reader, the chip card moves the carrier within the frame causing the roller cam to ride on the cam track of the lever thereby pivoting the lever and pressing the pressure plate against the inserted chip card, which is thus pressed against contacting elements mounted on said carrier. Apart from the complexity of the mechanism which adds to manufacturing cost and is prone to wear and failure, this chip card reader cannot be used for chip cards of different thicknesses since mutual arrangement of the carrier, the roller cam and the lever allows proper functioning of the card reader only with a chip card having a fixed predetermined thickness.
It is thus the object of the present invention to provide a chip card reading device adapted to receive chip cards having standard or double thicknesses, i.e. a thickness in the range of about 0.72 mm to about 1.68 mm, with the contacting force of the contacting elements of the reader on the contact pads of the card being kept within the allowable range of about 0.3 to about 0.5N in the reading position of the chip card.